View Full Version : Battery charging in the field

28th June 2017, 06:54 AM
Hi all I have just come back from a trip to Scotland with my son in his motor home. I noticed that we could only charge my camera batteries when on a camp site hooked up to mains power. I noticed on my return that go outdoors has small inverters that charge from a cigarette lighter in the car -- 12vdc-240ac with a built in S/O. Has anyone tried this idea out? Or any other system?
Kind regards mike

28th June 2017, 02:22 PM
Expro do a charger that runs of mains AND 12V (and their own batteries) although you may need to check comptability with Olympus chipped batteries.

28th June 2017, 04:19 PM
I just use a USB charger and a USB adapter for the car. It is not as fast as on the mains, but it works. Cost me $4 plus about $1.50 for a tiny digital DC voltmeter which I connected to the leads so I can keep an eye on the voltage. When it reads 8.4V unplugged, or about 9.3V charging, I know it is full.

28th June 2017, 09:39 PM
Thankyou both, I suppose it's horses for courses, I didn't think a USB would be powerful enough to charge the battery? How do you connect the em1mk2 battery? Can you post a link?
Kind regards Mike

28th June 2017, 10:01 PM
Here's a link to the ExPro charger for the BLH-1.

I have the equivalent model for the BLN-1 for my E-M5, works fine.



28th June 2017, 10:16 PM
Thanks Peter for the link and info.
Kind regards Mike

29th June 2017, 05:12 AM
Here is my home made jobbie...



As these knock off chargers don't usually have any kind of automatic cut-off they only have two pins, + and -. The voltage readout tells me how far along it is. Note that it reads about 0.12V higher under load. I know that a fully charged battery reads 8.39V unplugged, so I just turn it off if it reads 8.5V while charging. I wired a USB charger into the car with a little switch on it so I don't have to have the ignition on to power it through the cigarette lighter socket. This charger's output is only 500mA, which is why it is slow, but it works and as yet I have not felt the need to shell out €80 on a second battery.

29th June 2017, 05:47 AM
Hi Dan, thanks for posting the images, it doesn't look as completed as I thought I will take a look in maplins too see what they have,once againt thanks
Kind regards Mike

29th June 2017, 06:11 AM
These are the parts:
http://www.ebay.co.uk/itm/DSTE-Camera-Battery-Charger-UDC166-USB-Cable-for-Olympus-BLH-1-EM1-MARK-II-/182455838638?hash=item2a7b3727ae:g:iU4AAOSw2gxYo~F d

There is enough room inside the charger for the voltmeter. Just cut out a hole, glued it in and soldered the + to + and the - to -. *chr

I also stuck a piece of dark foil over the voltmeter as it was quite bright and a distraction while driving.

30th June 2017, 11:49 AM
We gave up on inverters in the motor caravan many years ago. You can get a 12v supply for laptops, printers, dongles, phones and BLN1 batteries. We don't carry a mains cable although we used to when skiing and using a small generator. Newer 12v seems to be USB but you can get adapters to standard 12v.

30th June 2017, 04:23 PM
My USB charger died today, just quit charging after 10 minutes on a 40% full battery. Oh well... have to think of something else.

2nd July 2017, 09:33 PM
I have used a simple 150w inverter plugged into 12v power supply socket in my car for several years now without any problems. I have charged laptop batteries, camera batteries and many other devices too. IMHO this is the best way if you have access to a 12v supply as you retain all the safeguards of your OEM charger. Good quality inverters can be had from between 20-30; some also include a separate USB socket. The majority of problems involving inverters occur when the load is too high. Charging camera batteries, iPads and laptops even at the same time should not be a problem.

3rd July 2017, 06:43 AM
Sound sensible enough...
I have ordered one of these to replace the insides of my charger.
http://www.ebay.at/itm/LM2596S-DC-DC-Step-Down-Schaltregler-Power-Supply-Modul-Charging-Model-Neu-/272295984613?hash=item3f661afde5:g:B0UAAOSwgY9XegN r
It can be adjusted to just under the 8.4V/1100mA max charging power so it can't overcharge the battery. I will just connect it to 12V in the car and see what happens. If that fails, I will look into the inverter option.

3rd July 2017, 07:55 AM
I have purchased a 300w 12dc-240ac inverter from Maplins. There is a normal 3 pin S/O and a USB port outlet. I can then attach the OLY battery charger to it. I have already charged the battery using this system and it still only takes two hrs to charge through the cigarette plug in my car. Not the cheapest way to go. Also if your considering going down this route ensure your car cigarette socket is live with out the ignition on. It also can be attached to the 12v supply directly with crocodile clips. Wth OLY batteries at circa 75 I considered this the safest way forward.
Kind regards Mike

4th July 2017, 06:27 AM
One thing I read about inverters is about their own drain on the battery, even with nothing attached. They draw around 0.3 to 0.4A themselves, which is three times what the Olympus charger draws. So one should be very careful NOT it leave it connected when not in use. Any experience with that?
There are a number of small ones here used for around 15-20, but still I will try my dedicated charger first. Parts are on the way... :cool:

4th July 2017, 07:31 AM
Most car batteries have an average capacity of around 80ah and a drain of about 0.4ah will take a week or so before the car battery is drained and that's assuming the car is not used at all. Some inverters have a low voltage warning. I have never had a problem despite forgetting to unplug the inverter for several days. Just don't go on holiday for a couple of weeks with your car in the garage with inverter plugged in!

4th July 2017, 08:14 AM
The unit I have purchased was very small, with idea being that it would be very portable. The drain advice by Dan is excellent, call me old fashioned but there is no way that I would even leave the inverter or any such device on, even standby, I do not leave my phones on charge overnight whilst I am asleep! Standby with televisions etc is a No No in my house not just because of the power usage!
Kind regards Mike

22nd July 2017, 11:58 AM
So far so good. The parts came and I put the thing together, and it works perfectly. I adjusted it to match the battery, 1100 mA at 8.4V, so it charges just as quickly as the original, and it tuns itself off when the battery is at 100%. Connected through a small switch directly to the car battery so no need to have the ignition on while charging. Total cost, 3. *chr

25th July 2017, 11:53 PM
The step down Lithium battery charger is a clever idea. I have just one caution for you.

At 8.4V you are right at the edge of the maximum charge voltage for two series connected cobalt based Li-ion cells. Charging at too high of a voltage can reduce battery life and can even be a safety concern. I don't know the composition of the OMD Li-ion batteries, but for a little peace of mind backing off to 8.2V might be safer. That is still above nominal cell voltage so it should charge fully. If you try reducing the voltage and it still charges you are still in good shape and may have longer battery life.

26th July 2017, 06:48 AM
You are right.
The actual voltage while charging is 8.24V. That is also what I get while the wall charger is charging. With no load it reads 8.4V. To be on the safe side, I have in fact reduced the current to 1050mA, and I plan to drop the voltage down another couple of tenths. I set it at its maximum to test how well it works, but I certainly don't want to risk harming the battery to save a few seconds of charging time. Nothing gets warm while charging... a good sign.
It also has a trimmer for adjusting the current detection, but I don't need to play with that much. The fully charged battery will not be sitting in the charger for long periods of time.

5th August 2017, 07:36 AM
Adjusting the charger to 8.2V (load-less) means it only charges the battery to about 96% before it turns itself off, so I set it back to 8.4V as before, but I will leave the current at 1050 mA. I charged it full from about 50% and nothing felt warmer than in the wall charger, so I figure I am safe.